Multistage rotary compressor



June 2, 1936. K. BAUMANN 2,042,496

MULTISTAGE ROTARY COMPRESSOR Filed Feb. 12, 1955 3 Sheets-Sheet 1 Inventor: Karl Bauumann,

Hi Attorney June 2, 1936. K. BAUMANN MULTISTAGE ROTARY COMPRESSOR Filed Feb. 12, 1955 s Sheets-Shet 2 Inve Karl umann, by 7* June 2, 1936.

K. BAUMANN MULTISTAGE ROTARY COMPRESSOR Filed Feb. 12,, 1955 3 Sheets-Sheet 3 Attorney.

Patented June 2, 1936 UNITED STATES -PATENT OFFICE Karl Baumann, Wihnslow, England, assignor to General Electric Company, a corporation of New York Application February 12, 1935, Serial No. 6,183 In Great Britain February 19, 1934 1 Claim.

This invention relates to multi-stage fluid compressors and pumps.

The object of the invention is to improve the efliciency of such machines and to simplify and 5 cheapen' their construction.

According to the present invention a multistage fiuid compressor or pump comprises two rotors mounted on parallel shafts and is formed with laterally extending plates partitioning the 10 machine into a series'of parallel chambers each rotor comprising a plurality of sets of blades and the sets of rotor blades on the one shaft being located in chambers alternating with those in which the sets of blades on the other shaft are 15 located, said chambers being shaped to constitute discharge passages for the respective rotor blades and being provided with axially directed outlets for passing the fluid to the set of blades of theother rotor through which the fluid 20 next passes.

The rotation of the impeller shafts is preferably in the same direction such as could be obtained by a motor driving the two impellers through a gear wheel and two pinions.

5 The design is such that the discharge from the impeller mounted on one shaft is taken to the eye of the impeller mounted on a second shaft and so on.

In order that the invention may be more clearly understood reference will now be made to the accompanying drawings which illustrate one suitable embodiment of the invention and wherein Fig. 1 is a plan view of a machine embodying the invention, part of the machine being shown 35 as a horizontal section through the shaft centres.

Fig. 2 is a section to a reduced scale on the line IIII of Fig. 1.

Fig. 3 is a section on the line III-III of Fig. 1.

Fig. 4 is a section corresponding toFig. 2 but 40 showing the modifications necessary for passing the fluid through a cooler.

In the drawings a number of parts on the left side of the machine correspond to parts on the right side, and where this occurs the refer- 45 ence numerals to the parts on the left side have been designated by the suflix a whilst the corresponding part on the right side has been designated by the sufiix b.

Referring to the drawings l represents the cas- 5 ing of the machine and 2a and 2b are the rotor shafts on which are mounted sets of rotor blades 3a and 317 respectively. The space within the casing is divided by lateral platesv l into a series of chambers 5.

55 Each alternate chamber 5 referred to herein by the reference 5a contains a set of the blades 3a whilst each of the intervening chambers designated by the reference 5b contains a set of the blades 3b. It is intended that in the arrangement shown each of the rotors will rotate in a counter 5 clockwise direction. 7

The chambers 5a and 5b are each shaped to constitute a fixed discharge passage for conducting the fluid discharged from the respective rotor blades located in the chamber in question 10 to the set of rotor blades in an adjacent chamber through which the fluid next passes.

Each of the chambers 5a accordingly comprises a portion Go (see Fig. 2) surrounding the set of blades 3a in question, a cross-over passage 1 and a portion 8b surrounding the shaft 2b and located between adjacent sets of rotor blades 3b. In each of the chamber portions 8b there is formed an annular convergent portion 9b terminating in a lateral outlet Illb. The fluid passes from each outlet lDb to the eye llb of the rotor blades 3b located in the next adjacent chamber.

Similarly as shown more clearly in Fig. 3 each of the chambers 5b comprises a portion 6b surrounding the blades 3b a cross-over passage [2 and a portion 8a located around the shaft 2a terminating in a convergent passage 9a and laeral outlet Hla.

It will be observed that in the arrangement shown the cross-over passages 1 are located on the under side of the machine whereas the pas-. sages I2 are located in the upper part of the machine.

Around each set of rotor blades 30. and 3b are diverging portions l3a and l3b respectively into which the fluid from the rotors is discharged whilst each of the passageways 9a and 9b preferably contain fins Ma and Mb respectively for the purpose of preventing vortices.

This fluid leaving a set of rotor blades 3a. will pass through the chamber portion 6a, cross-over passage 1 into the associated chamber portion 8b on the other side of the machine; thence it will pass through discharge passage 9b and outlet Iflb into the eye of the rotor blades 3b in the next chamber. From the rotor blades 3b the fluid will similarly pass into chamberportions 6b and thence through cross-over passage I2 to chamber portion Ba on the left side of the machine. From the chamber portion 8a the fluid will pass through passageway 9a and outlet Hla to the rotor blades 3a in the next chamber and so on passing alternately through a set of blades 30. and then a set of blades 3?). Referrlng to Fig. 4 the fluid will progress from too to bottom of the figure through each chamber in turn.

It will be appreciated that with such an arrangement the change of direction of the fluid is considerably reduced in comparison with usual arrangements since the path through an impeller and the discharge path from it are kept in the same plane, thus friction losses are appreciably reduced.

In order to keep friction losses low the peripheries of the passage portions 611 and 6b are preferably of an involute shape as clearly shown in the drawings.

The plates 6 may conveniently be of steel thus enabling smoother passages to be obtained and reducing the cost of construction as compared with cast iron due to the elimination of machining and chipping.

Furthermore, the construction may be so arranged that the joints in the various static parts such as those between the platesG and the easing 5 may be made'by welding or alternatively the structure may be supported by riveting or like methods of assembly.

The construction also lends itself readily to cooling between stages and Fig. 4 is a section corresponding to Fig. 2 of a chamber 5a which is modified to allow of the fluid being passed through a cooler during its passage between the rotor blades 3a and the outlet Ill). The chamber portion 6a is formed with a discharge passage l5, provided with baiiles I6 leading to the cooler (not shown), whilst the chamber portion 8b is formed with a passageway l1 similarly provided with baifles l8 which conducts the fluid from the cooler tothe chamber 81).

It will be appreciated that cooling will in general only be effected between some of the stages, for instance after leaving every third or fourth impeller blade depending upon the design of the apparatus.

I claim:

' A multi-stage rotary compressor including the combination of a fabricated casing having an outer wall, two rotors with parallel shafts and a plurality of impellers disposed in the easing, a plurality of substantially parallel plates extending laterally within the casing and welded to the outer wall to define a plurality of chambers, each chamber containing one impeller and a curved partition disposed centrally between the shafts to define together with said outer wall a channel for conducting fluid discharged from KARL BAUMANN. 

